java check if string contains only characters code example

Example 1: check if a string contains a character java

string.indexOf('a')

Example 2: how to check if a string contains only alphabets and space in java

class IsAlpha
{
    public static boolean isAlpha(String s) {
        return s != null && s.chars().allMatch(Character::isLetter);
    }
 
    public static void main(String[] args)
    {
        String s = "ABCD";
        System.out.println("IsAlpha: " + isAlpha(s));
    }
}

Example 3: how to check if a string contains only alphabets and space in java

class IsAlpha
{
    public static boolean isAlpha(String s) {
        return s != null && s.matches("^[a-zA-Z]*$");
    }
 
    public static void main(String[] args)
    {
        String s = "ABCD";
        System.out.println("IsAlpha: " + isAlpha(s));
    }
}